Fatty acid salts of amino alcohols



' Patented u FAT AC SALTS 0F m oALoonoLs Byron M. Vanderbilt, Terre Haute, Ind., assign orto net-c Solvents Corporation, Ten-e Haste, End, a corporation of Maryland No Drawing.

6 Claims.

My invention relstes to the use of the salts of monohydric m1. ohydroiw compounds as emulsifying agents, and the like. More particularly, it relates to the use of higher fatty acid salts of monohydric aminoalcohols as, emulsifying agents.

The term emulsion covers a. wide variety of products of varying characters which consist essentially of particles or. droplets of a liquid suspended in another liquid. Fsmiliar examples of emulsions are homogeneous mixtures of oil or wax and'water. Such mixtures are ordinarily obtainable only with the aid of a third substance, coonly designated as an emulsifying agent, which assists in the dispersion of one liquid within another and at the some time confers varying degrees of stability thereto, depending largely upon the particular liquids being treated, the properties oi the emulsifying agent employed, concentrations, temperature, etc. The emulsions so produced may be very fluid liquids, thick creams, or stiff jellies. Common emulsions are those produced by oil and water with the aid of some emulsifying agent. If the oil droplets are suspended in the water this type of emulsion is hnown as the oil-in-water (U/W) type. If the oil is the continuous phase of the emulsion and water droplets are suspended therein, the emulsion is the water-in-oil (W/O) type. The former type may be readily diluted with water and-the latter only with oil.

Emulsions 'often possess unusual and desirable properties per so. In many instances, however, they are employed as a means of obtaining suitable dilutions of various materials which may not be satisfactorily used in concentrated form. Emulsifying agents are used commercially for the production of emulsions suitable for many purposes including insecticides, disinfectants, or-

chard sprays, polishes, lotions, creams, inks, etc.

The selection of an emulsifying agent for a particular purpose is determined by such factors as stability of the material, its tendency to affect unfavorably any of the constituents of the dispersion, and the amounts required been incompletely esterified with high molecu- Application August 13, 1937, Serial No. 158,961

(Cl. Emit-40d) iii lar weight fatty acids, metallic soaps, etc. The properties of most of these materials, however, are such as to limit their general use.

I have now discovered that higher fatty acid salts of the aminoalcohols are particularly suited for use as emulsifying agents. The aminoalcohols which react with the fatty acids to form the emulsifying agents of my invention have the following. general formula:

wherein the substituents R1, R2, and R3 are either hydrogen atoms or alkyl groups, in which the sum of the hydrogen atoms represented by said substituents is less than three, and the sum of the carbon atoms represented by R1 plus R2 is less than four and greater than zero. Spe cific examples of the aminoalcohols included by" this formula are: 2-amino-1-propanol, 3-amino- 3-methyl-2-butanol, 3-amino- 2-methyl-4-hexanol, 5-amino-4-octanol, 2-amino-2-methy1-1- propanol, 2-amino-2-methyl-l-butanol, 2-amino-l-butanol, and 3-amino-2-butanol.

These new emulsifying agents and emulsions containing them may be prepared in a variety of ways. If, for example, it is desired to use the salts of the various aminoalcohols directly they may be prepared by adding the aminoalcohol to an equivalent amount of a higher fatty acid at room or elevated temperatures and in the pres-- ence or absence of an auxiliary solvent such as ethyl ether. The salts thus prepared may be added directly to a mixture of oil and water with vigorous agitation. Preferably, however, the emulsions utilizing the salt of the aminoalcohol are prepared in one of the following ways: First, the aminoalcohol and higher fatty acid are dissolved in a part of the oil and then the water and the rest of the oil are added alternately with good agitation. Second, a water solution of the aminoalcohol' and a higher fatty acid are first prepared and the oil run into this slowly with good agitation. Third, a solution of the aminoalcohol and higher fatty acid in all of the oil is prepared which emulsifies spontaneously when added to water. Fourth, the emulsification is brought about instantly by stirring together two solutions, one of water and the aminoalcohol, and the other of the oil and fatty acid.

The concentration of the emulsifying agents to be used will vary widely, depending upon the particular higher fatty acid salt of aminoalcohol employed, the emulsion to be prepared, the desired characteristics of the resulting emulsions, etc. I have found that fairly stable emulsionsof naphtha and 90% water may be monohydric aminoalcohols such as the aminohexanols, aminoheptanols, and aminooctanois, have a tendency to form emulsions of the waterin-oil type. The monohydric aminoalcohols containing more than eight carbon atoms, in general, are too water-insoluble, and therefore are not satisfactory to be used for the preparation of the emulsifying agents of my invention. The higher fatty acid salts of the monohydric aminoalcohols containing three or four carbon atoms will, in general,- form. emulsions of the oil-in-water type, and those emulsifying agents prepared from monohydric aminoalcohols containing five carbon atoms will, under diiierent conditions, form emulsions of either the W/O or O/W type.

In general, stoichiometric quantities of the aminoalcohol and fatty acid are used to give the emulsifying agents of my invention in order to impart desirable properties to the emulsions produced, but an excess of either material may be used without departing from the scope of my invention. In fact, a slight excess of one or the other constituent in certain cases gives more stable emulsions than when equivalent quantities of base and acid are used. Thus, in general, it may be stated that an excess of higher fatty acid used in the emulsifying agents will tend to increase the stability of a water-in-oil emulsion, and, conversely, an excess of amino- 'alcohol will tend to lend more stability to an and their use in emulsions, but it is to be under-,

stood that the invention is not to be limited thereby: To 0.02 mole of the monohydric aminoalcohol dissolved in 31 cc. of water there was added 0.02 mole of oleic acid dissolved in 38 cc. of petroleum naphtha boiling at 160-175 C. The mixture was then diluted with 200 cc. .of water, agitated vigorously for 3 minutes and allowed to stand at room temperature.

The oleate of 3-amino-2-butanol gave an emulsion of the O/W type, when prepared as indicated above, which separated into two layers within twenty hours. The oleate of Z-aminol-butanol gave an emulsion, when prepared as indicated above, which immediately separated into two layers, the upper being of the W/O type, and the lower, O/W. When a 5% excess of the base was used a one phase O/W emulsion was obtained, which separated in approximately twenty hours. Similarly, the oleate of Z-aniinoz-methyl-l-propanol gave an emulsion of the O/W type, which was stable for approximately five days. Using a 5% excess of the base increased the stability. When using the corresponding stearate, layer separation occurred in less than twenty-four hours.

It is to be understood that any of the higher fatty acids or mixtures thereof may be used for preparing the emulsifying agents of my invention. For example, any of the fatty acids or mixtures thereof obtained by the saponification of an animal or vegetable oil may be used whether they be saturated or unsaturated, substituted or not substituted. Examples of fatty acids that may be employed are lauric, myristic, palmitic stearic, arachidic, oleic, cruclc, linoleic, linolenic, clupanodonic and ricinoleic acids. I prefer to use acidscontaining from 12 to 18 carbon atoms since in general, fatty acids containing less than 12 carbon atoms are not as satisfactory as the higher members of the series. The following may be substituted for the petroleum naphtha of the specific examples cited above: vegetable or mineral waxes, fats, oils, greases, etc.

The emulsifying agents of my invention may be employed for the preparation of a large variety of emulsions. Any emulsions that may be prepared in which the emulsifying agent falls within the scope of my invention.

What I claim is:

1 A higher fatty acid salt of an aminoalcohol of the following general structural formula:

. NH: OH

R| I Q- I R: R: H V wherein the substituents R1, R2 and R3 represent components chosen from the class consisting of hydrogen atoms ,andalkyl groups having less than four carbon atoms, in which the sum of the hydrogen atoms represented by said substituents is less than three, and the sum of the carbon atoms represented by R1 plus R2 is less than four and greater than zero.

2. An oleic acid salt of an aminoalcohol of the following general structural formula:

wherein the substituents R1, R2, and R: represent components chosen from the class consisting of hydrogen atoms and alkyl groups having less than four carbon atoms, in which the sum of the hydrogen atoms represented by said substituents is less than three, and the sum of the carbon atoms represented by R1 plus R2 is less than four and greater than zero.

3. A higher fatty acid salt of 2-amino-2- methyl-l-propanol.

4. The oleic acid salt of 2-amino-2-methyll propanol.

5. A higher fatty acid salt of Z-amino-lbutanol.

6. The oleic acid salt of 3-amino-2-butanol.

BYRON M. VANDERBILT. 

